Telephone system.



PATENTED DEG. 1,1903.

G. RITTER. TELEPHONE SYSTEM. APPLICATION FILED AUG. 16, A189B.

5 SHEETS-SHEET 1.

N0 MODEL.

W... J H HU n w l v.. 1L

No. 745,388.l f PA['E1\I'I'B])'DECl l, 1903.

G. RITTER. TELEPHONE SYSTEM. APPLICATION FILED AUG, 1e, 189s. l NoMODEL. l 5 SHEETS-SHEET 2.v

g3 I. L @Ah/faded.'

THE Ncmms PETERS cm Pham-nwo.. wAsuwoTon, D. c.

c.. RITTER. TELEPH01\IB SYSTEM. l APPLICATION PVILEP UG.16, 1898.

5 SHEETS-SHEET 3.

N0. MODEL.

|t|||||| III 4 1@ Vat/ea ywwf fr. iff. n

PATENTED DEC. 1, 1903.

G. `RITTER. TELEPHONE SYSTEM. .APPLICATION FILED UG.16, 1898.

5 SHEETS-SHEET 4.

N0 MODEL.

me mams ravens cn. wow-Ln' 'PATBNTBD DBG. 1, 1903.

G. RITTER. TELEPHONEI SYSTEM.

APPLIATION FILED UGl, 1898.

asumTssHEnT 5.

N0 MODEL.

M w T|i4i|||i liwwflwl.; m T I\ 4 No. masse.

atented December 1, 1963;.

PATENT OFFICE.

GEORG RITTER, ou STUTTGART, GERMANY.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent N o.`745,388, dated.December 1, 1993. Application filed August 16, 1898. Serial No. 688,683.(No model.)

To a/ZZ whom it may concern/r.

Be it known that I, GEORG RITTER, a citi- Zen of the Empire ot' Germany,residing at Stuttgart, in the Em pire of Germany, have invented certainnew and useful Improvements in Telephone Systems; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

My invention relates to improvements in telephone systems, and inparticular to systems in which is employed a register device forregistering the number of messages sent over the subscribers circuit towhich said register device relates.

The object of myinvention is to provide a system in which a record isautomatically produced showing the number of times a subscriberstelephone-line is used.

An apparatus embodying myinvention comprises the combination, with atelephone system, of an electrically-operated register device for eachsubscribers line, a circuit in which'said register device isincluded,and means operated by the switchboard mechanism employed in making theconnection between said subscribers line and the central station orother stations for closing the circuit of the register device.

Among the many advantages of my invention are the following: Theregister device and its circuit may be introduced into telephonesystems, already in operation, as well as into new systems, with aminimum cost and in systems of the former class without interferingwilli the regular operation of the lines. Moreover, no separate orspecial circuit-closing apparatusis needed in the switchboard for use inthe register-circuit.

Myinvention will rst beldescribed in connection with the accompanyingdrawings and then particularly pointed out inthe claims.

In.the drawings, Figure l is a diagrammatic View of a telephone systemembodying my invention. Figs. 2 to 6, inclusive, are

similar views showing other forms of telephone systems embodying my saidinvention.

In Fig. l is shown a system of circuits embodying a central station, aplurality of substations, (two being shown,) a register device for eachsubstation, and circuits for the register devices. In this figure thefulllines indicate the talking-circuits, the broken lines show thecircuits for the register devices, and the dot-and-dash lines thetesting-circuits for testing the talking-circuits. As above stated, inthis figure two substations S' and S2 are illustrated, which areconnected to the centralV station by conductors l l and 2 2. In each ofthese conductors are included three jacks, (indicated at K and K2,respectively,)

as well as calling-annunciators N and N2, re-

spectively. For making connections between the substations the'plugconnector pairs A V A2 V2 A3 V3 are employed, while for calling thesubstations the switches L Ll L2a L22 L3 L3", as well as thecircuitchangers U U2 U3, are provided, the circuitchangers serving tocut in and out the central-station telephone F and-the respectiveclearing-out annunciators O O2 0 2. A battery or other source ofelectricity (indicated at W) is also supplied for the purpose of callingthe subscribers.

Referring now to the means for registering the number of times asubscribers line is in use, B is a battery for the registers, having itsnegative pole connected to the registers (indicated at Z and Z2) bymeans of a conductor 14 and branches I2 and 13, which extend to thesockets of the jacks K K2, respectively, and include the coils of thecorresponding registers, which may be of any suitable and well-knownconstruction. The positive pole of the battery B is connected,throughthe connections 15 and 6 and the branches of the latter, with thecorresponding points or contact-pieces ofthe levers I of thecircuitchangers -U U2 U2, in this case with the lefthand series of suchpoints. The fulcrums of the levers I are connected by conductors 16 withthe contact rings or shells ofthe answerplugs A A2 A2, which contactrings or shells, it is to be noted, fit snugly into the sockets of thejacks, so that upon the insertion of a plug the circuit of theregister-battery is closed. For the purpose of testing thetalking-circuits the right-hand points or contactpieces of the levers Iof the circuit-changers U' U2 U3 are connected by the conductor 5 5 andits branches with the positive pole of the register-battery B across thecondenser C. ItV

is to be understood, of course, that the-said IOO condenser serves toprevent the direct electrical communication through said conductor 5 5.Furthermore, the said conductor 5 5 is in electrical communicationthrough the conductors 17 17 with shells or rings on the plugs of thecalling-plug connectors V V2 V2, which serve for making connectionsbetween two subscribers lines. These plugs when inserted also makeelectrical connections with the sockets of the jacks K K2, therebyclosing the register-battery circuit at the jacks, although said circuitis not complete, owing to the fact that the condenser C is included init. The negative pole ofthe battery B is connected, by means of theconductor 11, which includes a resistance R, to the grounded pole of thecentral-station telephone.' It is to be understood that the shells orrings on the plugs of the plug-connectors A A2 A3 and V' V2 V3, at whichterminate the conductors 16 and 17, respectively, are insulated from thepoints of said plugs.

The production of connections between two substations follows in generalin the same manner as other exchange systems, it being borne in mind,however, that the answering of a substation cannot be doneindiscriminately with either of the two plugs of a pair ofplug-connectors, as in other systems, but must always be done with oneof the answerplugs A' A2 A2.

The method of testing aconductor to ascertain whether or not it is inilse prior to making a connection is similar to that in previoussystems, being done by touching one of the jack-sockets of the desiredline, which produces a click in the operators telephone. The circuit forproducing this test is, however, quite different from the usualtestingcircuit and will now be described. Let it be assumed thatsubstations S and S2 are connected as shownin Fig. 1 and that theoperator has touched the jack-socket K2 with the tip ofthe plug V2. Itwill be seen that the testing-circuit, when the tip of the plug V3 istouching the jack-socket K2, is as follows: from the positive pole ofbattery B to the conductor 15, thence over the latter to one side of thecondenser C, from the other side of condenser C, along conductor 5 tothe cord 17 of plug V2, through the corresponding jack-socket toconductor 13, to th'e jacksocket, which is touched by the tip ot theplug V3, along cord 18 of said plug to switch L22, thence through theupper contact-point to lever III, over the same and its correspondingbranch wire to conductor 7, thenceto and through the operator-stelephone F to the junction of conductors 10 and 11, Vover conductor 11and the resistance R to conductor 14, and thence to the negative pole ofthe battery B. From this it will be seen that the testing-circuitincluded the condenser C. Consequently at the moment ot' touching thejack-socket K2 with the tip of the plug V2 the condenser will becharged, and at the moment of removal of the tip of said plug Vs fromsaid socket the condenser will be discharged, thereby producing a clickin the operators telephone and giving notice that the line 2 is busy.

Instead of a condenser a high resistance may be employed, as will befully understood by those skilled in the art,it being obvious that thepurpose of the condenser is to prevent the closure of theregister-circuit over the testing-circuit, while at the same timeallowing the testing-circuit to give a sound in thc operators telephonewhen a test is made if the line tested is then in use. The highresistance operates in substantially the same manner.

In describing the operation ot' the register device it willbe assumedthat the substation S desires to communicate with the substation S2 andthat therefore the register j, belonging to the first-mentionedsubstation, must register one conversation or use of the line chargeableagainst substation S in case the connection with substation S2 is made.For the purpose of doing this the pair of plugconnectors A2 V2 areemployed. Before taking the plug A2 away from its seat thecentral-station telephone Fis connected to the conductors 18 and 18 bymoving the levers I, Il, and IH of circuit-changer U2 to the right,(inthe present construction,) so that by the insertion of the plug A2 inthe socket ot' the jack K/ the register Z is connected over conducters12 12 and by means of the socket of the jack K the contact ring or shellof the plug A2 and conductor 16 with the conductor 5 5 through the leverI of the circuit-changer U2, and, furthermore, is also connected withthe positive poleof the batteryB in open circuit through the condenserC. Thelatter,l1owever, does not allow any current to iiow over thecircuit. justdescribed, so that therefore the register Z' does notoperate. The connection with the positive pole of the battery B is onlyfor the purpose of rendering possible the testing of the conductor 1 1for apurpose hereinafter explained. After the central-station operatorhas learned from the subscriber `atsub station S that the latter desiresto converse ICC IIO

with the subscriber at substation S2 the plug p V2, afterthepreviously-described test has been made, is inserted in a socket ofthe jack K2, the station S2 called by pressing the switch L22, and thenby moving the circuitchanger U2 to the left the clearing-out annunciatorO2 is switched onto the conductor 1S 18 and the central-stationtelephone thereby cut out. Upon theshiftingof the circuit-changer U2 tothe left, as above mentioned, its lever I becomes included in circuitwith conductor 6 instead of with conductor 5, as before, whereby thecircuit of the register-battery is closed and the register operated toregister one use of the line to station S.

The course of the current of the registercircuit is as follows: from thenegative pole of the battery B through conductors le and 12, overthecoils of the register to the socket of the plugged jack K', fromthere through the contact ring or shell of the plug A2, along theconductor 16 to the leverI of the circuitchanger'U2, over said lever toits left-hand point, and along conductors 6 and 15 to the positive poleof the battery B. By this closure of the circuit the current from theregister-battery B continues to flow during the entire period that the`line to substation S is in use, so that by a suitable construction ofthe register apparatus not only the number of conversations chargeableto substation S', but also the duration of each, may be recorded.

The above-described register system illustrated in Fig. 1 assumes eitherthat the central-station telephone is connected when not in use with theconductors 18 18 of the plugconnector conductors or that said telephoneis switched onto said conductors before taking a calling-plug into use,which may be done simultaneously with the switching off of theclearing-out annunciator, as shown in Fig. 1. If, however,thecentral-station telephone is not normally in connection with theconductors 18 of all the plug-connectors when the latter are out of useand if, also, there is no means operated by the operation of thecircuit-changer for closing the particular conductor 18 onto thecentral-station telephone when taking such conductor into use, then itis preferable to employ an automatic circuitcloser for theregister-circuit, one form of which is shown. at G2, Fig. 2, and anotherform at I, Fig. 3, each of which is arranged to-close theregister-circuit at that point. The reason for this is that if myinvention be applied to a system employing a clearing-out annunciatoralways in circuit with the plugconnectors then upon the insertion of acalling-plug, as V2, the current in the registercircuit would flow overthe conductors 15 and 6, lever I of the switch V2, conductors 16, 12,and 14, and thereby cause the register to opcrate, which isadisadvantage to be avoided, since it is not desired to registeraconversation until a connection between two stations has been completed.

Theabove-mentioned course of the current in the register-circuit is notpossible in the construction shown in Fig. 1 if the switch U2 is kept inits left-hand position before the completion of a connection or if aseparate circuit-closer is used, as at G2 in Fig. 2.

In Figs. 2 and 3 are shown register-circuits provided, respectively,with the above-mentioned separate circuit-closers. These figurescorrespond exactly with regard vto the illustration in Fig. l of theseparate parts and are altered from this only with regard to thearrangement relative to each other. In both figures theregister-magnettogether with its armature are shown, the Alatterbeing soarranged that upon being attracted byits magnet it will turn the wheel Dforward one tooth and release the wheel D2 (which represents theescapement-wheel of a clockwork) during the time that said armature isattracted, so that not only will the conversation be counted, but alsothe duration of the same will be recorded. A jack K of the conductor 1is shown, with a corresponding answer-plug A2 inserted, the calling-plugV2 being still upon its seat out of operation, while the circuit-changerU2 is turned one hundred and eighty degrees with relation to itsarrangement in Fig. 1, wherefore the clearing-out annunciator O2, aswell as the central-station telephone, are arranged at the upper part ofthe figures. In Fig. 2 the additional circuitclosing device G2 is soarranged at the seat of the plug V2 and in the conductor 6 6, betweenthe right-hand contact piece or point of the lever I of thecircuit-changer U2 and lthe positive pole of the register-battery B,

that this additional circuit-closing device will be open during the timewhen the said calling-plug V2 rests in its seat and closed when the saidplug is lifted fromsaid seat. Furthermore, so long as the calling-plugV2 is not in use and not lifted from its seat a closure of the circuitbetween conductors 6 and 16 does not produce an operation of theregisternZ.

In order to call the substation connected with conductor 1, it isnecessary to switch the central-station telephone on to the conductors18 18 of the pairof plug-connectors in use, from which it results thatthe circuit-changer U2 in Fig. 2 must be maintained in its position tothe left from immediately after the answer-plug A2 is inserted in itsjack up to the time when the calling-plug V2 is inserted in itscorresponding jack, in which position roo y of the circuit-changer itslever I connects the y conductors 16 16 with the conductors 5 5,whereby, as follows from the description in Fig. 1, no operation of theregisters takes place. The latter can only occur afterthecircuit-changer yU2 has been shifted to its right-hand position, wherebythe leverI connects the conductors 16 16 with the conductor 6 and thecurrent of the register-battery takes the following course: from thenegative pole of the battery B, over the conductors 14 14 and 12 12,through the register Z to the socket of the jack K., and from theretothe vcontactring of ythe plug A2, through the same, and

through conductors 16 16, lever I, conductors 6 6, and circuit-closingdevice G2 to tive pole of the battery B.

In the central station, where the calling of the posithe desiredsubstation is done by theopera- Under the switch L2b a lever I is soarranged that by means of a block of insulating material arrangedbetween the two the downward movement of the said switch mustv cause themovement of the lever I. In the normall position the leverl contactswith a point or contact-piece which is in connection with the Iconductor5 5,.while when moved downward it contacts with a point or contact-piececonnected to the conductor 6 6. After the production of a connectionbetween two substations and for the purpose of calling the desiredsubstation the switch L22 is pressed down, whereby the lever I contactswith the contact-piece of the conductor 6 6, and the battery B is in aclosed circuit with the register Z, whereupon the current of theregister-circuit travels exactly as described with relation to lFig. 1.In order to hold the levers I and L2b so as maintain theregister-circuit closed during the whole time of a conversation in orderthat the register may record the duration of a conversation, the lever Iis connected with the armature II of an electromagnet M, the lattermagnet being included in the conductors 6 6 between the contact-piece ofthe leverI and the positive pole of the battery B, the saidelectromagnet being energized by the current from the registerbattery,and thereby holding its armature and the lever I downward during thetime ot' the connection of the two substations.

In the above-described arrangements the registers Z' Z2 are connectedwith the sockets of the jacks and the connector-conductors are used alsoas test-conductors. In those exchange systems which do not possessspecial (or separate) testing-conductors the registers may be connectedwith the jacks by means of the talking-conductors, as showngin Fig. l.In this gure, as in Fig. 1, there are two substatious S and S2, whichare united to the central station by conductors l l and 2 2, and at thelatter place all the substation-conductors are connected to a commongrounded conductor 9 9.

For the purpose of making connections between two substations the pairsA V A2 V2 of plugs are provided, which are in turn connected to thecircuit-changers Ul U2. The levers I of these circuit-changers serve forthe control of the register-circuit, while the levers II and III areemployed for alternately cutting in or out the clearing-out annunciatorsO' O2 of the central-station telephone F. The lever H II2 serves forthrowing the testbattery P or the galvanometer T onto or oft from thecalling-plugs V V2. It is to be observed, moreover, that levers I II IIIare connected so as to move simultaneously, whereas the lever H2 may beindependently moved. The switch L is common to all the pairs ofplug-connectors. The plugs A V A2 V2, the rst of which serve asanswerplugs, the latter as'calling-plugs, have their shafts divided, asin Figs. l to 3, into two parts insulated from each other. The points ofthe plugsA A2 are connected to the register-conductors 16 16, while thepoints of plugs V V2 are united to the arms I-I H2 of thecircuit-changer U U2 through the conductors 17 17. In both species ofplugs the rear parts of the shafts are connected with the conductors 1818 of theplug-connectors. The construction of the plugs is such that'their points contact with the springs while their rear portions contactwith the sockets of the jacks into which they may be inserted.

The registers Z' Z2 Z2 Z2 are connected on one side with the negativepole of the battery B and on the other side with the respectivesubstation-conductors l, 2, 3, and 4 between the calling-jacks and thecallingannunciators NN2N2 N4. The positive pole of the battery Bisconnected to the left-hand contact-point of the levers I of thecircuitchangers U' U2 by means ot' the conductors 6. Furthermore, thepivotal point of the lever I is in electrical communication with thepoints or ends of the answer-plugs A A2 through the conductors 16 16.

In this exchage system the production of connections between twosubstations and the necessary testing of the conductors as to Whether inuse or not takes place in the usual manner, and may therefore be assumedto be understood.

A description of the register apparatus will now be given, it beingassumed that substation S2 desires to communicate with anothersubstation. In order to ascertain what is the number of the substationdesired by the subscriber at substation S2, the operator places theanswer-plug A2 in one of the sockets of the jacks K2, whereby theregister Z2 is connected with the pivotal point of the lever Iof thecircuit-changer U2 through the conductors 13 and 2, the spring of theplugged jack K2 raised by the point of the plug A2, and through theconductor 16 connected to said point of plug A2 and to the said pivotalpoint of the lever I. The central-station telephone F is presumed to bein connection with the conductors 18 18 of the pair of plug connectorswhich are to be used before the plug A2 is inserted in the properjack-socket, the levers of the circuit-chan ger U2 occupying theirright-hand position, whereby the register-circuit is interrupted at thelever I of said circuit-closure. The switching of the telephone F ontothe conductor of the substation desired by substation S2, tested inadvance by means of the plug V2, is necessary, whereby it results thatafter a complete connection the switching oft' ot the telephone and thesimultaneous switching on of the clearing-out annunciator by shiftingthe circuit-closer U2 to the left may then follow. By this shifting ofthe lever to the left the conductor 16 16 is electrically connected overthe lever I of the circuit-closer U2 with the conductor 6 6, and therebywith the positive pole of the registerbattery, whereby the latter is ina closed circuit with the register and is thus operated to register onenumber. The course of the current is as follows: from the negative poleof the battery B over the conductors 13 13 and 2 2 to the raised springot the plugged jack K2, from there over the point of the plug A2, alongthe conductor 16 16, over lever Iof the circuit-closer U2 to conductor 66, and from there to the positive pole of the battery B.

IIO

Since all the talking-circuits and therewith all the registers areconnected with the grounded conductor 9 over the calling-annunciators,therefore by the closure of the registerbattery circuit over any one ofthe registers a branch current would also flow over all the otherregisters. As will be understood from the foregoing description, if thecurrent from battery B is allowed to pass, for example, over the`register Z2 a current from conductor 14 14 may also flow through theregisters Z' Z3 Z4, as well as through the correspondingcalling-annunciators N N3 N4, to the grounded conductor 9 and from thisthrough the annunciator N2 over conductor 2, the raised spring ofthejack K2, and the point of the plug A2 to conductor 16, and thence tolever I of the circuit-closer U2 and by way of the same and conductor 6to the positive pole of the battery B. As the branch currents would notonly iiow over the registers Zl Z3 Z4, but also over thecalling-annunciators N', N2, and N4, there would be a false registryupon said registers and an undesirable falling of the correspondingannunciators, to overcome which the latter are constructed to have ahigh resistance, the registers a low resistance, and the battery B isadapted only for the resistance of the latter.

It it is desired to avoid the loss of current from the battery B,.due tothe branch currents above referredto, a circuit interrupter or breakermay be united to the armatures of the register-magnets, by which for thetime being the correspondingtalking-conductor between thecalling-annunciator and the point of closure of the register isinterrupted during the period of registration. This form of apparatus,however, is only shown in the drawings for the register Z2 in'order notto complicate the illustration of the general construction.

In the above-described register apparatus a registration follows uponthe completion of a connection between two substations, whereby itremains unconsidered whether the called substation answersornot.Thissortofapparatus will be used at those places where theadministration of the telephone system is so conducted that a separatefee is charged as a remuneration for employment of the'l operator inmaking a connection; but in the places where only those conversationswhich actually take place are counted the closing of theregister-battery must be postponed until the called substation makesanswer. This requirement may be accomplished by so connecting a batteryand an electromagnet to the conductorr uniting the substations that themagnetic condition of said electromagnet will be altered by alterationsin the electric conditions of the line-wire to one of the two connectedsubstations, a circuit-closing apparatus being so connected to thearmature of the said electromagnet, which circuit-closing'apparatus isarranged to close the register-circuit, whereby upon an alteration ofthe attractive power of the electromagnet the said circuit-closingapparatus is operated. The completion of the registration by means ofthe above-described apparatus is done best bythe substation called andin the simplest manner by the lifting of the telephone of saidsubstation from its hook, as that is the proper point of time for theregistration.

The practical construction of an apparatus I corresponding to theabove-described systems permits various arrangements of theelectromagnets and battery for effecting the closure of theregister-circuits, and the ad` vantage of one or the other arrangementdepends upon the kind of telephone Lsystem to which it is to be applied.

In Fig. 5 an arrangement is shown which is well adapted for illustratingand practically carrying out the above-described form. In this figurethe switches, calling-batteries, and other devices and circuits notnecessary for explaining the register apparatus are omitted for the sakeof perspicuity. In said figure it is assumed that the substation' Sdesires to communicate with substation S2, and the making of aconnection between the two has progressed so far that it only remains toswitch in the clearing-out annunciator.

In addition to the register apparatus thus far described the followingsupplementary apparatus is shown in Fig. 5, viz: In thetalking-conductors 18 l8 of the pair of plug-connectors A V a pivotedlever T is so inserted that in its normal position it contacts .with thecircuit-closer Y, while an armature T' of an electromagnet M2 ispositively connected to said lever T. Furthermore, the lever Tis coupledby alink of insulating material to a lever D, so that both levers T andD will move simultaneously. To the link is connected one end of a springX, which tends to draw both levers away from the magnet M2. Theconductor 16 is connected to the said lever D,

The lever I of the circuit- The link;

circuit-closer U carries on its right-hand end a leaf-spring whichcontacts with the lever T upon the movement of the circuit-closer U'toward the right while the said lever T upon being forced toward theright contacts with the contact-point which is connected to the coils ofthe magnets M and M2 and upon being forced to the left contacts with thecon' tact-point connected to the conductor 18 18. In the position of thecircuit-closeriU indicated in Fig. 5, in which the telephone F isconnected to the conductor 18, the circuitclosing point D of the leverDy lies against the spring end R of the lever I, and the arm T liesagainst the contact-point Y, whereby the conductor 16 is connected tothe positive IOO pole of the battery B 'over the lever D, con-, V

tact-point D', arms R' and R2 of the lever I, conductor 5, condenser C,and conductor 6, so that the conductor l can be tested byan operatorother than the one who answers the call of substation S'. The reason forthis is that systems such as just described are commonly very extensiveand require the attention of several operators. Consequently it mightoccur after substation S' had notied the central that it desired to beconnected to some other substation-say substation S2, for example-andwhile waiting for such connection that another operator would receive arequest from still another station for a connection with station S', andit is important that the construction be such that a test of theconductors to substation S' will show it to be busy even though it isnot then actually connected with the substation (as S2) for which itcalled. If the circuit-closer U is moved to the right for the purpose ofswitching in the clearing out annunciator, the spring Q forces the leverT and D to move with ittoward the right until the lever T is stopped bythe contact Y', whereupon the spring bends or yields and finally slipspast the end of said lever, whereby the magnets M' and M2, together withthe battery B', are inserted in the conductor 1S 1S of thetalkingcircuit, over leverT and the contact-point Y'. Furthermore, thelever D lies with its contactpoint D2 against the contact-point P, whichis connected to the conductor 5 in order to preserve the possibility oftesting the conductor 1 for the purpose hereinbefore described. Inconsequence of the switching of the battery B' onto thetalking-conductor 18 the current of said battery passes through themagnet M', contact-point Y'-, lever T, conductor 18, clearing-outannunciator O, the point of the plug A, the lifted spring of the pluggedjack K', conductor 1, lever H' of the substation S', telephone F',earth-plate E', to and through earth-plate E2 of the substation S2,thence over bell G2, lever H2, conductor 2, the spring of the pluggedjack K2, the point of the plug Y, conductors 18, and magnet M2 back tothe battery B'. Thereupon as soon as the substation-telephone F2 islifted from its hook in order that the subscriber may answer his callthe circuit of 'the battery B' is broken during the time that the leverH2 moves from the contact-point of the bell G2 to the contactpoint ofthe telephone F2, whereby the magnet M2 is demagnetized, and the arm Tcontacts with the contact-point Y, and the arm D is moved so that itscontactpoint D2 rests against the arm R2 of the lever I. Thereupon theregister-battery circuit is closed over the register Z', the currenttaking the following course: from the negative pole of the battery B,over conductors 14 and 12, through register Z' to the socket of theplugged jack K', thence through the plug A, conductor 16, lever D,contact-point D2, arm R2 of the lever I, conductors 6 and 15, to thepositive pole of the battery B.

It is to be understood that when the switch U is thrown to the left thespring on its end will pass the end of the lever T, owing to the factthat movement of the lever T to the right is prevented by thecontact-point Y, thereby compelling the said spring to yield and slipunder the end of the said lever T, thereby resuming its originalposition.

In order to prevent the clearing-out annunciator from being released bythe battery B', the armature T is so arranged that when drawn up it willclose a grounded circuit through spring T2, contact-point Y2, conductor4, and ground E. This grounding of the circuit has in view also thepreventing of a false registration, which would otherwise occur throughthe breaking of the circuit of battery B' at the time of hanging up thetelephone F' upon the hook I-I' at the end of a conversation, whichbreaking of the said circuit will be without effect upon the battery B',where the grounded circuit is provided. By this means the current ofbatteryB'is divided through two grounded circuits, a small part of thecurrent flowing through the clearing-out annunciator to the ground atsubstation S', while the remainder ilows to the ground through theconductor 4f, the earth forming a common return for both portions of thecurrent to the ground connection of substation, from which place thecurrent returns to the battery B' overconductors 2 and 18, whereby thecurrent of battery B' cannot be interrupted by an interruption of thecircuit at substation S', since it may still now through conductor 4 tothe ground.

Although by a proper operation of the above-described apparatus a falseregistration is practically excluded, yet as in practice errors mayoccasionally occur which will requirea negative operation of theregister in order to correct its error l provide a device for thispurpose which may be actuated by the operator without inconvenience.This is shown in Fig. 6, which ligure corresponds in general arrangementto the construction shown in Fig. 1, the operation of the registersystem being readily understood from the description heretofore given inconnection with said Fig. l. The correcting or negative-registeringapparatus will now be described.

Referring to Fig. 6, D' D2 are switches inserted between the left-handcontact-points of the levers I of the circuit-changers U' U2 and theconductors 6 6, which lead to the posi tive pole of the register-batteryB'. vThese switches D' D2 are arranged when in their normal positions toconnect the said left-hand contact-points of levers I with the saidpositive pole of the register-battery B', and, when pressed downward, tocontact with a point forming the terminal of a conductor 7, which leadsto the negative pole of another battery B2, which I will term thecorrection-battery. By this arrangement if an error has been made on oneof the registers it may be corrected by pressing the corresponding lOOIIO

switch D or D2, thus sending a reverse current over the correspondingregister and operating it in a negative direction, the positive pole ofthe correction-battery B2being permanently connected through conductorlet with the negative pole of the register-battery B' in order that thecircuit may be complete. As, however, when the switches D or D2,respectively, return to their normal position the correspondingregister-circuit will again be closed and again register another number,it is necessary to press downward the switch D or D2, respectively,twice without allowing it to return to its normal position between suchtwo downward movements, whereby two negative registrations will be made,and then when the one positive registration is made by the return oftherespective switch D or D2 to its normal position one of the two negativeregistrations will be counterbalanced, and the final result in theregister will be one number less than before the correcting operationwas commenced, which is here assumed to be the result intended. Insteadof employing the switches D D2 a special plug connector X may be used,which is connected to the conductor 7. By inserting this plug in one ofthe jacks of the line whose register it is desired to operate negativelythe current from the correctingbattery B2 will be sent out over saidregister and the previous erroneous registration deducted. In a registerapparatus employed in connection with such a correcting device it isnecessary that polarized armatures be used for the register-magnets, andeither two register devices must be employed for each system, one torecord the positive registrations and the other the negativeregistrations or errors made, or the register must have twoelectromagnets, these magnets beingarranged to move the register-dialsin opposite directions, as will be plain from Fig. 6, which shows theregister Zprovided with two electromagnets operatingin conjunction witha common polarized armature, each magnet being included in the conductor1.2 in parallel. The magnet M' attracts the armature by the current fromthe battery B', while the o magnet M2 repels said armature. When thebattery B2 is thrown onto the register-circuit by pushing down the keyD', the reverse operation oi the armature occurs.

At L L2 in the drawings are shown keys included in the circuit with theansweringplugs A A2, respectively. The function of# these keys is toenable the central exchangel. In a telephone system, the combinationwith a jack, a register-circuit open only at the jack and at one otherpoint, a register device included in said circuit and means forenergizingthe circuit, of a plug insertible in the jack and arranged toclose the register-,circuit at that point, and means operated incompleting the connections between substations and arranged to close theregister-circuit at the other point where it is open, whereby the cir- Ycuit is closed.

2. In a telephone system, the combination with a jack, aregister-circuit open only at the jack and at another point, a registerdevice included in said circuit, and means for energizing the circuit,of a plug iusertible in the jack and arranged to close the circuit atthat point, means for closing the register-circuit at the second point,mechanism operated in completing the connections between substations forplacing in operative condition the said means for closing the,register-circuit, and means operated bythe subscriber at the calledsubstation for setting in operation the said register-circut-closingmeans.

In testimony whereof I affix my signature in presence of two witnesses.

GEORG RITTER.

Witnesses:

AUGUST DRANTZ, H. WAGNER.

